"To strengthen the cadres still more and to make
provision for such men as desire to earn their living in the
army, certain classes of soldiers are allowed to engage for 21
years, and by this means earn a pension. The terms are as
follows:

a. Warrant Officers, Staff Sergeants, and Sergeants of the corps
of Army Schoolmasters have the right after 11 years
service, and those of other arms after 9 years service to
engage for 21 years.

b. Corporals, bombardiers, second corporals, bandsmen, pipers
and artificers may be allowed with the consent of the commander
of the battalions, &c., to engage for 21 years after 9
years service; trumpeters, drummers, and buglers after 11
years service.

c. Other soldiers may have leave given them by the commander
of the battalion, &c., to engage for 21 years, if they have
earned two "good conduct" badges. (But as a rule this
leave is granted only to men in special posts such as
officers servants, mess waiters, &c.).

REFERENCE:

GRIERSON, J.M. Scarlet Into Khaki: The British Army on the Eve
of the Boer War. Greenhill Books, London, 1988, p. 24.